Pyxine yunnanensis M. X. Yang & Li S. Wang

Yang, Mei-Xia, Wang, Xin-Yu, Liu, Dong, Zhang, Yan-Yun, Li, Li-Juan, Yin, An-Cheng, Scheidegger, Christoph & Wang, Li-Song, 2019, New species and records of Pyxine (Caliciaceae) in China, MycoKeys 45, pp. 93-109 : 93

Pyxine yunnanensis M. X. Yang & Li S. Wang sp. nov. Figure 4

Holotype.

CHINA, YUNNAN PROVINCE, Yongren Co., Lagu Vil., 1050 m elevation, 26°23.239'N, 101°25.120'E, on rock, 4 Dec 2013, L. S. Wang et al. KUN-L 13-41372. GenBank accession No.: ITS = KY611870, mtSSU = KY751377.

Description.

Thallus saxicolous, up to 7 cm in diam., closely appressed to the substrate. Lobes radiating, irregularly branched, plane to slightly concave, 0.2-1.0 mm wide, subround to truncate at the apices. Upper surface pale grey to yellowish-grey, sparsely pruinose at the lobe tips or epruinose. Lower surface brownish-black, rarely pale brown, rhizines indistinct, sparse to moderately abundant, brownish-black to black. Isidia and soredia absent. Medulla pale yellow in the upper part, white in the lower part. Apothecia abundant, 0.2-0.8 mm wide, constricted at base, plane to possibly convex; margin black. Hymenium height 80-120 μm; hypothecium light brown to brown, internal stipe white; spore brown with two cells, 10-15 × 4-7 μm. Upper cortex K+ yellowish, UV+ yellow; medulla K–, C–; containing lichexanthone, chloroatranorin (minor), zeorin and unknown terpenes (detected by TLC).

Habitat and distribution.

Growing on rocks around 1050-1650 m elevation in secondary forests in a dry to semi-arid environment; known only from Yunnan.

Etymology.

The epithet yunnanensis refers to the province of the type locality of the species.

Notes.

Pyxine yunnanensis is characterised by small and saxicolous thalli, rather small narrow apothecia (up to 0.8 mm in diam.), a white internal stipe and the presence of lichexanthone. Pyxine minuta Vain. (up to 3 cm in diam.) resembles P. yunnanensis (up to 7 cm in diam.) in its small thalli and the presence of lichexanthone, but differs in that its internal stipe is absent or indistinct and it has a white medulla ( Awasthi 1982). Pyxine pyxinoides ( Müll. Arg.) Kalb and P. elixii Kalb also grow on rocks, but P. pyxinoides differs from P. yunnanensis in that it has a white medulla, an indistinct internal stipe of the apothecia and smaller ascospores (10-15 × 4-7 μm) than those of P. pyxinoides (10-16 × 4.5-8.0 μm). Pyxine elixii can be distinguished by its orange medulla and lack of lichexanthone ( Elix 2009).

Pyxine yunnanensis is closely related to P. berteriana in that they have a similar type and size of apothecia and lichexanthone is present, but Pyxine berteriana differs in that it occurs in incorticolous habitat and has a yellow medulla and a yellow medulla of the stipe.

Selected specimens examined (KUN).

CHINA: YUNNAN PROVNCE: Yongsheng Co., Dongjiang of Renhe Town, 1130 m elev., 26°20.448'N, 101°06.908'E, on rock, 7 Dec 2013, L. S. Wang et al. 13-41413; Shawan Village of Renhe Town, 1160 m elev., 26°19.449'N, 101°05.200'E, 7 Dec 2013, L. S. Wang et al. 13-40643, 13-40694, 13-40686, 13-40641, 13-40684; Lijiang City, east of Jinan Bridge, 1310 m elev., 26°47.725'N, 100°25.640'E, on rock, 8 Dec 2013, L. S. Wang et al. 13-40596.